One might expect a play written by TV and radio comedy panel game stalwart Sandi Toksvig to be a whimsical offering with some rather arch slivers of satire.

In fact, her two-hander Bully Boy is an essentially joke free exploration of the corrosive effect of war on the men who fight it.

There is a touch of politics – including a mandatory dig at Thatcher – and some criticism of the use of electro-convulsive therapy, but the themes are essentially timeless, even though the aftermath of the invasion of Iraq is the trigger for a storyline which also includes flashbacks to the Falklands.

The two characters are Private Eddie Clark, who is Burnley-born (a fact that actually becomes pertinent to the plot) and the subject of an investigation by Major Oscar Hadley, a military policeman who has been wheelchair –bound since his service in the Falklands.

The play, in a seamless series of short scenes linked by visual images screened on a pair of TV sets, charts the shifting relationship between the two men, divided by rank, class and educational attainment but with some surprising points of contact. The relationship is always fraught and sometimes improbable, but ultimately becomes a touching one.

Performed without an interval, Bully Boy has its flaws but is an intense and involving piece of theatre. In Alistair Cheetham’s lean and propulsive production it has resulted in two very impressive performances from Alex Watkins as Clark and Gareth Dickinson as Hadley. Word perfect and completely in character for 95, dialogue-intensive minutes, the two actors do superbly well, negotiating many emotional peaks and troughs.

We first see Oscar Hadley on screen at the start of the play. He is giving evidence to some tribunal and from the very beginning we detect that there is anguish and real humanity behind Gareth Dickinson’s well-educated tones and precise delivery. It is anguish that eventually develops into rage and regret in a performance that is truly affecting.

Private Clark, who has been accused in connection with the death of an Iraqi boy, begins as a gormless squaddie, unthinkingly loyal to his mates, but embarks on a troubling psychological journey that brings out a tender, poetic side to his personality. Again, these transitions are exceptionally well negotiated by Alex Watkins.

Bully Boy is the latest in a sequence of powerful, small-cast, minimalist productions staged by the Thespians in the LBT’s cellar and is well worth seeing. It runs until Saturday, when there is also a matinee.